1. Field of the Invention
The invention relates to a storage system. More particularly, the present invention relates to a coordinated storage system for a peer-to-peer network.
2. Description of the Related Art
Conventional storage systems such as network attached storage systems (NAS) and storage area network systems (SAN) suffer from limited scalability, and their performance and reliability are dependent on the performance and reliability of their respective components.
Peer-to-peer systems become more and more widespread in distributed applications because of the simple and scalable architecture of peer-to-peer systems. A pure peer-to-peer network consists of a collection of peer nodes that operate exactly in the same way, that is, there is no distinction between peer-to-peer nodes in terms of functionality. A peer-to-peer network typically employs a distributed hash table (DHT) to provide a look-up service for locating a data object such as a stored file from a group of peers. A peer-to-peer network architecture is a promising architecture because of its good scalability, load balancing and fault tolerance. However, conventional peer-to-peer networks lack high level management functions due to the absence of a global view of the system's state. Conventional peer-to-peer systems have been applied to distributed storing or sharing of data and files in wide area network (WAN) environments and are rarely found in corporate computing infrastructures because of the missing high level management functions.
Conventional main stream architectures for a corporate level storage system consist of network attached storages and storage area networks. These conventional network architectures have a limited degree of scalability because a portion of the data or metadata access goes through a centralized server. Therefore, conventional NAS and SAN based storage systems become increasingly insufficient in meeting the growing demand for more and more storage capacity. Another limiting factor of conventional NAS and SAN architectures is that they are designed and built using more reliable components to achieve a low fault tolerance. However, these components are generally very expensive. As storage systems grow larger and larger to meet the growing demand for storage capacity, less reliable components such as commodity hardware are introduced for cost efficiency reasons. Consequently, the fault tolerance of a conventional NAS and SAN storage system becomes less.
FIG. 1 shows a diagram of a pure peer-to-peer storage system. Such a conventional peer-to-peer system relies on distributed protocols to maintain network connectivity and health state of peers such as storage peers. These distributed protocols need a high bandwidth and high algorithm complexity.
A major disadvantage of a pure peer-to-peer network architecture as shown in FIG. 1 resides in its lack of global state information being available in the whole system.
Accordingly, there is a need for a storage system with an architecture, which avoids broad bandwidth usage and high complexity.